Lighting device

ABSTRACT

Provided is a lighting device, including: a printed circuit board; one or more light emitting units formed on the printed circuit board; a resin layer which is formed on the printed circuit board, in which the light emitting units are embedded; a diffusion plate formed on an upper side of the resin layer, whereby an entire thickness of the lighting device can be reduced, and when the product is designed, a degree of freedom in design can be improved because flexibility is secured.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit under 35 U.S.C. §119 of KoreanPatent Application Nos. 10-2012-0023422, filed Mar. 7, 2012;10-2012-0023423, filed Mar. 7, 2012; and 10-2012-0023424, filed Mar. 7,2012, which are hereby incorporated by reference in their entirety.

BACKGROUND

1. Field of the Invention

The present invention relates to a technical field of a lighting device,and more specifically, to a structure of a lighting device which enablesan entire thickness to get thinner and can secure light efficiency.

2. Description of the Related Arts

An LED (Light Emitted Diode) device is a device which converts anelectrical signal to infrared rays or tight using a compositionsemiconductor property. Unlike a florescent lamp, since the LED devicedoes not use harmful substances such as mercury and the like, it has alow possibility to cause environmental pollution and a long life spancompared to a conventional light source. Also, it is advantageous thatthe LED device spends low electricity compared to the conventional lightsource and has excellent visibility and low brilliantness due to a highcolor temperature.

Accordingly, a current lighting device has been developed from astructure, in which a traditional light source such as a conventionalincandescent tamp or a florescent lamp is used, to a structure, in whichthe aforesaid LED device is used as a light source particular, by usinga light guide plate as disclosed in Korean Laid-Open Patent PublicationNo. 10-2012-0009209, the lighting device which performs a surfacelight-emitting function has been provided.

FIG. 1 and FIG. 2 schematically illustrate a conventional lightingdevice 1 which (performs a surface light-emitting function. Referring toFIG. 1 and FIG. 2, the conventional lighting device 1 is configured suchthat a flat light guide plate 30 is disposed on a substrate 20, and aplurality of side view type LEDs 10 (only one LED being illustrated inthe drawings) are disposed on a side of the light guide plate 30 in anarray shape.

Light (L) incident to the light guide plate 30 from the LEDs 10 isreflected to an upper part by a minute reflection pattern or areflection sheet 40 which is provided onto a bottom surface of the lightguide plate 30 and is emitted from the light guide plate 30. Then, thelight is emitted to the upper part of the light guide plate 30 and thusis provided to the outside through an external housing 50 made of atransparent material. Like the conceptual view as illustrated in FIG. 2,the lighting device 1 may be configured such that a plurality of opticalsheets such as a diffusion sheet 31, prism sheets 32, 33, a protectivesheet 34 and the like are further added between the light guide plate 30and the external housing 50.

The aforesaid lighting device 1 functions to uniformly supply light tothe outside. The light guide plate 30 is a component which functions toimprove brightness of the light device 1 and to uniformly supply light.Also it is a kind of plastic mold lens to uniformly transmit the lightemitted from a light source (LED). Accordingly, the light guide plate 30is elementally used as an essential component of the conventionallighting device 1, but, due to a thickness of the light guide plate 30itself, there is a limitation to make the thickness of an entire productthinner. As a material of the light guide plate 30 is not flexible, itis disadvantageous that it would be difficult to apply the light guideplate to the external housing 50, and thus a product plan and designcannot be easily changed.

Also, as the light is emitted from the side of the light guide plate tothe outside, light loss is generated, thereby reducing light efficiencyand brightness of the lighting device.

Moreover, because the LED which is a point light source is used, eventhough it is changed to a surface light source, there is a limitation toembody various lighting designs.

PRIOR ART REFERENCE Patent Reference

Korean Laid-Open Patent Publication No. 10-2012-0009209

BRIEF SUMMARY

The present invention has been made keeping in mind the above problemsoccurring in the related art. An aspect of the present inventionprovides a structure of a lighting device, which is configured such thata resin layer instead of a light guide plate is used to guide lightemitted from a light emitting unit to the outside, thereby enabling anentire thickness of the lighting device to get thinner.

Another aspect of the present invention provides a structure of alighting device, which can secure reliability while improving a degreeof freedom in product design as the lighting device itself hasflexibility.

Still another aspect of the present invention provides a structure of alighting device which is configured such that a light reflection unit isdisposed on a side of a resin layer so that light loss generated fromthe side of the resin layer can be minimized, and light efficiency canbe improved.

Also, still another aspect of the present invention provides a lightingdevice, which is configured such that such that an indirect radiationunit is formed on a side of a surface light-emitting unit so that aflare effect can be generated, thereby realizing design differentiationof the lighting device.

According to an aspect of the present invention, there is provided alighting device including: a printed circuit board; one or more lightemitting units formed on the printed circuit board; a resin layer whichis formed on the printed circuit board, and in which the light emittingunit is embedded; and a diffusion plate formed on an upper side of theresin layer.

According to the present invention, it is advantageous that the numberof light emitting units can be reduced and an entire thickness of thelighting device can be thinner by removing the light guide plate andguiding light using the resin layer.

According to the present invention, the lighting device is formed usingthe flexible printed circuit board and the resin layer so thatflexibility can be secured and a degree of freedom in product design canbe improved.

Moreover, according to the present invention, it is advantageous thatthe reflectance of light can be improved, the improvement of brightnesscan be maximized, and a uniform surface light source can be providedbecause the reflection member and the reflection pattern, which arestructures capable of efficiently reflecting the light emitted from thelight emitting units, are provided.

Also, according to the present invention, because the first opticalsubstrate or the second optical substrate having the optical pattern isformed such that the air gap is provided in the adhesive layer, a hotspot and a dark space can be inhibited from being generated from thelight shielding pattern, and the reliability of components adhered tothe adhesive layer can be secured. Also, it is advantageous that thelighting device without a significant difference between opticalproperties can be realized, and it would be possible to accurately alignthe components.

Also, according to the present invention, light loss can be minimizedbecause the light reflection unit is provided, thereby improvingbrightness and illuminance of the lighting device.

Also, according to the present invention, it is advantageous thatvarious lighting effects using a flare phenomenon can be realized andthe lighting devices of various designs can be implemented because theindirect radiation unit for reflecting light to the side of the surfacelight-emitting unit is disposed.

Also, according to the present invention, it is advantageous that a softillumination effect can be realized without a separate light emittingunit because the illumination effect is realized using light emitted tothe side of the resin layer.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of the present invention, and are incorporated in andconstitute a part of this specification. The drawings illustrateexemplary embodiments of the present invention and, together with thedescription, serve to explain principles of the present invention. Inthe drawings:

FIG. 1 and FIG. 2 schematically illustrate a structure of a conventionallight device.

FIG. 3 illustrates the subject matter of a lighting device according tothe present invention.

FIG. 4 illustrates a structure in which a bead and a reflection memberare added to the lighting device of the present invention as illustratedin FIG. 3.

FIG. 5 illustrates a structure in which the reflection member and anoptical sheet are added to the lighting device of the present inventionas illustrated in FIG. 3.

FIG. 6 illustrates a structure in which an adhesive layer is formed inthe lighting device of the present invention as illustrated in FIG. 5.

FIG. 7 schematically illustrates a structure in which the lightingdevice according to the present invention is applied to a headlight forvehicles.

FIG. 8 through FIG. 11 illustrate a structure in which a lightreflection unit is added to the lighting device of the present inventionas illustrated in FIG. 3 through FIG. 6.

FIG. 12 is a graph illustrating the measurement results of brightnessand illuminance based on whether or not the light reflection unit isincluded.

FIG. 13 through FIG. 16 illustrate a structure in which an indirectradiation unit is added to the lighting device of the present inventionas illustrated in FIG. 3 through FIG. 6.

FIG. 17 is an image illustrating a real operation state of the lightingdevice according to the present invention.

DETAILED DESCRIPTION

Exemplary embodiments according to the present invention will now bedescribed more fully hereinafter with reference to the accompanyingdrawings so that those having ordinary skill in the art can easilyembody. This invention may, however, be embodied in different forms andshould not be construed as limited to the exemplary embodiments setforth herein. It is to be understood that the form of the presentinvention shown and described herein is to be taken as a preferredembodiment of the present invention and that various changes andmodifications may be made in the invention without departing from thespirit and scope thereof. Also, in the following description, it is tobe noted that, when the functions of conventional elements and thedetailed description of elements related with the present invention maymake the gist of the present invention unclear, a detailed descriptionof those elements will be omitted. Reference will now be made in greaterdetail to a preferred embodiment of the invention, an example of whichis illustrated in the accompanying drawings. Wherever possible, the samereference numerals will be used throughout the drawings and thedescription to refer to the same or like parts.

The present invention relates to a lighting device using an LED, whichis a light emitting unit, as a light source. The gist of the presentinvention is to provide a structure of a lighting device, which caninnovatively reduce an entire thickness of the lighting device byremoving a light guide plate and replacing it with a resin layer, andcan also secure flexibility and reduce the number of light sources.

Moreover, the lighting device according to the present invention can beapplied to various lamp devices such as a lamp for vehicles, a lightingdevice for hone use and a lighting device for industrial purpose, whichrequire illumination. For example, in a case where the lighting deviceis applied to the lamp for vehicles, it can be also applied toheadlights, car indoor illumination, door scuff, backlight and the like.Additionally, the lighting device according to the present invention canbe applied to the field of a backlight unit applied to a liquid crystaldisplay device. In addition to this, the lighting device can be appliedto illumination related all fields which have been developed andcommercialized or can be implemented according to future technicaldevelopment.

FIG. 3 illustrates the subject matter of a lighting device according tothe present invention.

Referring to FIG. 3, a lighting device according to the presentinvention includes: a printed circuit board 110; one or more lightemitting units 130 formed on the printed circuit board 110; a resinlayer 150 which is formed on the light emitting units 130 so that thelight emitting units 130 is embedded in the resin layer, and whichguides emitted light to a diffusion plate 290; and the diffusion plate290 which uniformly diffuses incident light and emits the light to theoutside. Furthermore, a prism sheet and a protective sheet may befurther provided into an upper part or a lower part of the diffusionplate 290, even though this is not illustrated in the drawing.

The printed circuit board 110 means a board in which a circuit patternis formed on a substrate, namely, a PCB. In particular, in the presentinvention, it would be preferable that the printed circuit board isformed as a flexible printed circuit board (FPCB) to secure uniformflexibility.

The light emitting units 130 are configured such that one or more lightemitting units are arranged on the printed circuit board 110, therebyemitting light. The light emitting units 130 of the present inventionmay be composed of side view type light emitting diodes. That is, alight emitting diode having a structure in which emitted light isemitted in a lateral direction rather than going straight up may be usedas the light emitting units 130 of the present invention. Thus, thelighting device according to the present invention is configured suchthat the light emitting units 130 composed of the side view type lightemitting diodes are disposed in a direct type, and the resin layer whichfunctions to diffuse and reflect light is utilized so that the light isdiffused and guided in a direction of the diffusion plate 290, therebyreducing the number of tight emitting units and innovatively reducing anentire weight and thickness of the lighting device.

The resin layer 150 is formed in an upper part of the light emittingunits 130 and the printed circuit board 110. The resin layer 150diffuses and guides light emitted from the light emitting units 130forward. That is, the resin layer 150 is formed in a structure in whichthe light emitting units are embedded, thereby functioning to diffusethe light emitted from the light emitting units 130 to a lateraldirection. That is, the resin layer 150 may perform the function of aconventional tight guide plate.

The resin layer 150 of the present invention may be basically composedof a material which can diffuse tight. For example, the resin layer 150of the present invention may be composed of a ultraviolet curing resinincluding a oligomer. More specifically, the resin layer 150 may beformed using resin which has a urethane acrylate oligomer as a main rawmaterial. For example, resin in which the urethane acrylate oligomerwhich is a synthetic oligomer is mixed with a polymer type which ispolyacryl may be used. Of course, a monomer in which IBOA (isobornylacrylate), HPA (Hydroxylpropyl acrylate, 2-HEA(2-hydroxyethyl acrylate),which are low boiling point and diluted type reactive monomers, aremixed may be further included. A photo initiator (e.g.1-hydroxycyclohexyl phenyl-ketone and the like) or an antioxidant may bemixed as an additive. However, the aforesaid contents are only oneexample. In addition to this, the resin layer 150 of the presentinvention may be formed of all resins which have been developed andcommercialized or can be embodied according to future technicaldevelopment, and can perform the function to diffuse light.

According to the present invention, thanks to the existence of the resinlayer 150, the thickness occupied by the conventional light guide platecan be innovatively reduced, and the entire product can be made thinner.Also, because the lighting device has flexibility, it may be easilyapplied to a curved surface and a degree of freedom in product designmay be improved. Furthermore, the lighting device may be applied toother flexible display devices.

The diffusion plate 290 is formed in an upper part of the resin layer150 and functions to uniformly diffuse light emitted through the resinlayer 150 all over the surface. The diffusion plate 290 may be generallyformed of acryl resin. However, the present invention is not limited tothis. In addition to the acryl resin, the diffusion plate 290 may beformed of all materials of high transmission plastic such aspoly-styrene (PS), poly(methyl methacrylate) (PMMA), cyclic olefincopolymers (COC), polyethylene terephthalate (PET), resin, which canperform the diffusion function.

At this time, an air layer (i.e. a first air gap 280) may be furtherformed between the diffusion plate 290 and the resin layer 150. Thanksto the existence of the first air gap 280, the uniformity of lightsupplied to the diffusion plate 290 may be increased. As a result, theuniformity of light diffused and emitted through the diffusion plate 290can be improved. At this time, to minimize the deviation of light whichtransmits the resin layer 150, a thickness H1 of the first air gap 280may be formed in a range of 0 to 20 mm. However, the present inventionis not limited to this. The thickness may be appropriately changed asnecessary.

FIG. 4 illustrates a structure in which a bead and a reflection memberare added to the lighting device of the present invention as illustratedin FIG. 3.

Referring to FIG. 3 and FIG. 4, the resin layer 150 of the presentinvention may further include a plurality of beads 151 in a shape inwhich the beads having a hollow (or an air-void) formed in an inner partthereof are mixed and diffused. The beads 151 function to improve lightreflection and diffusion properties. For example, when light emittedfrom the light emitting units 130 is incident to the beads 151 of aninner part of the resin layer 151, the light is reflected andtransmitted by the hollow of the beads 151, and thus is diffused andconcentrated. The light is then emitted to the diffusion plate 290. Atthis time, a reflection and diffusion rate of the light are increased bythe beads 151, so that an amount and uniformity of the emitted lightsupplied to the diffusion plate 290 later are improved. As a result,brightness of the lighting device can be improved.

A content of the beads 151 may be appropriately adjusted to obtain adesired light diffusion effect. More specifically, the content of thebeads may be adjusted in a range of 0.01 to 0.3% based on a total weightof the resin layer. However, the present invention is not limited tothis. That is the light emitted from the light emitting unit 130 in aside direction is diffused and reflected through the resin layer 150 andthe beads 151 so as to travel in an upper direction. The beads 151 maybe formed of any one selected from silicon, silica, glass bubble, PMMA,urethane, Zn, Zr, Al₂O₃, and acryl. A diameter of the beads 151 may beformed in a range of 1 μm to 20 μm. However, the present invention isnot limited to this.

A reflection member 120 of the present invention is formed on an uppersurface of the printed circuit board 110 and has a structure in whichthe light emitting units 130 are formed to pass through the reflectionmember 120. The reflection member 120 according to the present inventionis formed of a material having high reflection efficiency, therebyenabling light loss to be reduced. The reflection member 120 may beformed in a film shape and may include a synthetic resin in which awhite pigment is diffused and contained so that light reflection anddiffusion properties can be realized. For example, titanium oxide,aluminum oxide, zinc oxide, lead carbonate, barium sulfate, calciumcarbonate and the like may be used as the white pigment. Polyethyleneterephthalate, polyethylene naphtaenate, acryl resin, poly carbonate,polystyrene, polyolefin, cellulose acetate, weather resistant vinylchloride and the like may be used as the synthetic resin. However, thepresent invention is not limited to this.

The reflection pattern 121 may be formed on a surface of the reflectionmember 120. The reflection pattern 121 functions to uniformly transmitlight to the diffusion plate 290 by scattering and diffusing theincident light. The reflection pattern 121 may be formed in such amanner that the reflection pattern 121 is printed on a surface of thereflection member 120 using a reflective ink including any one of TiO₂,CaCO₃, BaSO₄, Al₂O₃, Silicon and PS. However, the present invention isnot limited to this. Also, the reflection pattern 121 may have astructure having a plurality of protruding patterns and may be formed ina prism shape, a lenticular shape, a lens shape or a combination shapethereof to improve a light scattering effect. However, the shape is notlimited. Also, a cross-sectional shape of the reflection pattern 121 maybe formed in a structure having various shapes such as a triangularshape, a quadrangular shape, a semi-circular shape, a sinusoidal shapeand the like.

FIG. 5 illustrates a structure in which the reflection member and anoptical sheet are added to the lighting device of the present inventionas illustrated in FIG. 3.

Referring FIG. 3 to FIG. 5, the lighting device of the present inventionmay further include: a first optical sheet 170 formed on an uppersurface of the resin layer 150; and a second optical sheet 190 formed onthe first optical sheet 170. Also, an optical pattern 183 may be furtherformed on an upper surface of the first optical sheet 170 or a lowersurface of the second optical sheet 190. One or more optical sheets maybe additionally formed on the second optical sheet 190.

The optical pattern 183 formed on the upper surface of the first opticalsheet 170 or the lower surface of the second optical sheet 190 may beformed as a light shielding pattern formed to inhibit the concentrationof light emitted from the light emitting unit 130. For this, it isrequired to align between the optical pattern 183 and the light emittingunit 130. At this time, to secure fixing strength after performing thealigning, the first optical sheet 170 and the second optical sheet 190are adhered to each other using an adhesive layer which will beexplained hereinafter.

The first optical sheet 170 and the second optical sheet 190 may beformed using a material having excellent light transmission. As oneexample, PET may be used.

The optical pattern 183 disposed between the first optical sheet 170 andthe second optical sheet 190 basically functions to inhibit theconcentration of light emitted from the light emitting unit 130. Theoptical pattern 183 may be formed as a light shielding pattern so that alight shielding effect can be realized in a predetermined part toinhibit a phenomenon in which an optical property is deteriorated oryellowish light is generated due to excessively strong light strength.The light shielding pattern may be formed by performing a printingprocess to the upper surface of the first optical sheet 170 and thelower surface of the second optical sheet 190 using a light shieldingink.

The optical pattern 183 may be realized as one optical pattern so as toperform the function to partially shield and diffuse light rather thanthe function to completely shield the light and adjust a light shieldingand diffusing degree. Furthermore, more specifically, the opticalpattern 183 according to the present invention may be realized in anoverlapping print structure of complex patterns. The overlapping printstructure means a structure which is implemented by forming one patternand printing another pattern shape on an upper part thereof.

As one example, the optical pattern 183 may be implemented in astructure in which the diffusion pattern formed on a lower surface of apolymer film in a light emitting direction using a light shielding inkincluding one or more materials selected from TiO₂, CaCO₃, BaSO₄, Al₂O₃and Silicon overlaps with the light shielding pattern formed using alight shielding ink including Al or a mixture of Al and TiO₂. That is,the diffusion pattern is formed on the surface of the polymer film byperforming a white printing process, and thereafter, the light shieldpattern is formed thereon. In reverse, the patterns may be formed in adouble structure. Of course, it would be obvious that the formationdesign of the patterns may be variously changed in consideration of theefficiency and strength of light and a shading ratio. Also, the patternsmay be formed in such a tripe structure that in a sequential laminatedstructure, the light shielding pattern, which is a metal pattern, isformed in a middle layer, and diffusion patterns are implemented,respectively in an upper part and a lower part thereof. In this triplestructure, the patterns may be implemented by selecting the aforesaidmaterials. As one preferred example, based on the triple structure inwhich one diffusion pattern of diffusion patterns is implemented usingTiO₂ having excellent reflectance, another diffusion pattern isimplemented using CaCO₃ and TiO₂ together having excellent safety andcolor sense, and the light shielding pattern is implemented using Alhaving excellent hiding power, the efficiency and uniformity of lightcan be secured. In particular, CaCO₃ functions to decrease the exposureof yellowish light, and thus functions to finally implement white light,so that the more stable efficiency of light can be implemented. Inaddition to CaCO₃, inorganic materials having a large particle size anda similar structure such as BaSO₄, Al₂O₃ and Silicon beads and the likemay be utilized. Moreover, in view of the efficiency of light, it wouldbe preferable that the optical pattern 183 is formed by adjusting apattern density in such a manner that the pattern density is reduced asthe optical pattern is moved far from the light emitting direction ofthe LED light source.

FIG. 6 illustrates a structure in which an adhesive layer is formed inthe lighting device of the present invention as illustrated in FIG. 5.

Referring to FIG. 3 to FIG. 6, the lighting device of the presentinvention may further include an adhesive layer 180 formed between thefirst optical sheet 170 and the second optical sheet 190. A second airgap 181 may be further formed on the adhesive layer 180. That is, theadhesive layer 180 forms a spaced space (the second air gap 181) aroundthe optical pattern 183. By applying an adhesive material to remainingparts, the adhesive layer 180 may be implemented in a structure in whichthe first optical sheet 170 and the second optical sheet 190 are adheredto each other. Also, one or more optical sheets may be additionallyformed on the second optical sheet 190. The structure including thefirst optical sheet 170, the second optical sheet 190, the adhesivelayer 180 and the optical pattern 183 may be defined as an opticalpattern layer A.

The adhesive layer 180 may formed in a structure which the adhesivelayer surrounds around the optical pattern 183, and the second air gap181 is formed in the remaining parts or a structure in which the secondair gap 181 is formed around the optical pattern 183. Thus, it may berealized to align it by bonding the two optical sheets to each other.That is, a bonding structure of the first optical sheet 170 and thesecond optical sheet 190 may function to fix the printed optical pattern183.

At this time, the adhesive layer 180 may be formed using a thermosettingPSA, a thermosetting adhesive, UV curing PSA type materials. However,the present invention is not limited to this.

At this time, the first air gap 280 as set forth in the explanation ofFIG. 3 may be formed between the second optical sheet 190 and thediffusion plate 170. Thanks to the existence of the first air gap 280,the uniformity of light supplied to the diffusion plate 290 mayincrease. As a result, the uniformity of light which is diffused andemitted through the diffusion plate 290 may be improved. At this time,to minimize the deviation of light which transmits the resin layer 150,a thickness of the first air gap 280 may be formed in a range ofexceeding 0 but not exceeding 20 mm. However, the thickness is notlimited to this. As described in the explanation of FIG. 3, thethickness may be appropriately designed and changed as needed.

Also, as described above, one or more optical sheets may be additionallyformed on the optical pattern layer (A) as necessary, even though thisis not illustrated.

FIG. 7 schematically illustrates a structure in which the lightingdevice according to the present invention is applied to a headlight forvehicles.

Referring to FIG. 7, a lighting device 100 a according to the presentinvention is formed using a flexible printed circuit board and a resinlayer. The lighting device itself has flexibility. Accordingly, asillustrated in FIG. 7, the lighting device may be easily mounted to aheadlight housing for vehicles H in which flexure is formed. Thus, adegree of freedom in design of a complete product combined with thehousing may be improved. In spite of the improvement of the degree offreedom in design, uniform brightness and illuminance may be alsosecured. Meanwhile, FIG. 7 shows that the lighting device as illustratedin FIG. 3 is mounted. However, this is only one example. The lightingdevices as illustrated in FIG. 4 to FIG. 6 may be mounted.

FIG. 8 through FIG. 11 illustrate a structure in which a lightreflection unit and a light reflection unit supporting unit are added tothe lighting device of the present invention as illustrated in FIG. 3through FIG. 6.

Referring to FIG. 8 through FIG. 11, the lighting device according tothe present invention may further include a light reflection unit 160which is disposed on any one of one side and another side of the resinlayer 150. The light reflection unit 160 guides so that light emittedfrom the light emitting unit 120 is emitted to an upper part, andperforms a guide function to inhibit the light from be emitted to theoutside through a side of the resin layer 150. The light reflection unit160 may be composed of a white resist which is a material havingexcellent light reflectance. Additionally, the light reflection unit maybe composed of a synthetic resin in which a white pigment is diffusedand contained, or a synthetic resin in which metal particles having anexcellent light reflection property are diffused. At this time, titaniumoxide, aluminum oxide, zinc oxide, lead carbonate, barium sulfate,calcium carbonate and the like may be used as the white pigment. In acase where metal powders are included, Ag powders having excellentreflectance may be included. Also, a separate fluorescent whiteningagent may be additionally included. That is, the light reflection unit160 according to the present invention may be formed using all materialshaving excellent light reflectance, which have been developed or can beimplemented according to future technical development.

Meanwhile, the light reflection unit 160 may be directly molded andconnected to the side of the resin layer 150 or may be adhered theretousing a separate adhesive material (or an adhesive tape).

Moreover, the light reflection unit 160 may be connected to the resinlayer 150 using a separate a light reflection unit supporting unit 161.

According to this, as the light reflection unit 160 is formed on theside of the resin layer 150, light bleeding may be inhibited from beinggenerated in the side of the resin layer 150, thereby reducing lightloss and increasing light efficiency. Furthermore, brightness andilluminance of the lighting device may be improved in comparison ofequal electricity. Also, the light emitting units 130 and the resinlayer 150 may be safely sealed by further forming the light reflectionunit supporting unit 161 on the outer surface of the light reflectionunit 160, thereby improving durability and reliability of the lightingdevice.

FIG. 12 is a graph illustrating the measurement results of brightnessand illuminance based on whether or not a light reflection unit isincluded. Graph A represents brightness (nit) and graph B representsilluminance (lux). Referring to FIG. 6, compared to the lighting devicehaving a structure in which the light reflection unit is not mounted, itcan be confirmed that the lighting device having the light reflectionunit of the present invention shows the improvement of brightness andilluminance in the range of about 30 to 40%. Thus, according to thereduction in light loss, light efficiency is improved. Furthermore, itcan be confirmed that even though the number of the light emitting unitsis reduced, the same brightness and illuminance is implemented.

FIG. 13 through FIG. 10 illustrate a structure in which an indirectradiation unit is added to the lighting device of the present inventionas illustrated in FIG. 3 through FIG. 6. In particular, (a) of FIG. 13illustrates a plane view of the lighting device and (b) of FIG. 13illustrates a cross-sectional side view of the lighting device in whichthe indirect radiation unit is added to FIG. 3.

For an easy explanation, the lighting device as illustrated in FIG. 3 toFIG. 6 will be hereinafter referred to as a surface light-emitting unitX.

Referring to FIG. 13 to FIG. 16, the lighting device according to thepresent invention is composed of the surface light-emitting unit X andthe indirect radiation unit Y formed on a side of the surfacelight-emitting unit X. Here, the surface light-emitting unit X is thelighting devices as illustrated in FIG. 3 to FIG. 6, and is a part whichconverts light irradiated from the light emitting unit to a surfacelight source and emits the light to the outside. Also, the indirectradiation unit Y is a part which implements a light leak effect (or aflare effect) by reflecting the light irradiated from the light emittingunit of the surface light-emitting unit X and generating reflectionlight. Meanwhile, (a) of FIG. 13 illustrates that the indirect radiationunit Y is formed on the entire side of the surface light-emitting unitX. However, this is only one example. The indirect radiation unit may beformed only on a part of the side of the surface light-emitting unit X.

Since the configuration of the surface light-emitting unit X isidentical with that of the lighting device of FIG. 3 to FIG. 6 asdescribed above, the explanation thereon is omitted.

The configuration of the indirect radiation unit Y is composed of thelight reflection unit 161 formed on the side of the surfacelight-emitting unit X. The light reflection unit 160 may be formed to bespaced apart from the surface light-emitting unit X, more specifically,the resin layer 150 of the surface light-emitting unit X in apredetermined distance. Hereinafter, a spaced space between the surfacelight-emitting unit X and the light reflection unit 160 is defined as anindirect radiation air gap 162.

When light emitted from the light emitting unit 130 is emitted through aside of the resin layer 150, the light reflection unit 160 reflects theemitted light, thereby forming reflection light (or indirect light).Thus, the light which is lost at the lighting device is again reflectedby the light reflection unit 160, so a flare phenomenon in which lightsoftly spreads is generated. Also, by using the phenomenon, variousillumination effects which can be applied to indoor and outdoorinteriors and car illumination may be realized.

Meanwhile, to maximize the aforesaid flare phenomenon, the indirectradiation air gap 162 may be further formed between the light reflectionunit 160 and the surface light-emitting unit X. Thus, the light emittedto the side of the resin layer 150 is scattered at the indirectradiation air gap 162, and the scattered light is again reflected by thelight reflection unit 160, thereby maximizing the flare phenomenon.

The light reflection unit 160 may be composed of a material havingexcellent light reflectance, namely, a white resist. In addition tothis, the light reflection unit 160 may be composed of a synthetic resinin which a white pigment is diffused and contained, or a synthetic resinin which a metal particle having an excellent light reflection propertyis diffused. Titanium oxide, aluminum oxide, zinc oxide, lead carbonate,barium sulfate, calcium carbonate and the like may be used as the whitepigment. In a case where metal powers are included, Ag powders havingexcellent reflectance may be included. Also, additionally, a separatefluorescent whitening agent may be further included.

Meanwhile, in the drawing, it is illustrated that a height of the lightreflection unit 160 is identical with heights of the printed circuitboard 160 and the resin layer 150. However, this is only one example.The height is not limited. For example, the height may be extended to aside of the diffusion plate 290 as necessary, or may be formed to beextended only to a side of the resin layer 150.

Also, it is illustrated that the light reflection unit 160 isperpendicular to a horizontal plane. However, this is only one example.As needed, the light reflection unit may be implemented in a shape inwhich the light reflection unit is inclined so as to form apredetermined angle to the horizontal plane.

The lighting device according to the present invention may furtherinclude a support unit 163 which surrounds an outer surface of the lightreflection unit 160 and a lower part of the surface light-emitting unitX as illustrated in FIG. 13 to 16. The support unit 163 functions tosupport and protect each configuration of the lighting device. Itsmaterial is not limited. For example, the support unit 163 may becomposed of a metal material or a plastic material. Also, it may beformed of a material having fixed flexibility. Thus, by further formingthe support unit 163, the surface light-emitting unit X and the indirectradiation unit Y may be safely sealed, thereby improving durability andreliability of the lighting device.

FIG. 17 is an image illustrating a real operation state of the lightingdevice according to the present invention.

Referring to FIG. 17, it can be confirmed that the light irradiated fromthe light emitting unit of the surface light-emitting unit X isconverted to the light emitted from the surface and is thus emitted tothe outside. Also, it can be confirmed that a flare effect is generatedfrom the indirect radiation unit V as the light is scattered and isagain reflected, and thus soft indirect light is emitted to the outside.That is, according to the present invention, indirect light having afixed shape can be additionally realized without an additional lightemitting unit. Also, the illumination effects of various designs can beachieved.

As previously described, in the detailed description of the invention,having described the detailed exemplary embodiments of the invention, itshould be apparent that modifications and variations can be made bypersons skilled without deviating from the spirit or scope of theinvention. Therefore, it is to be understood that the foregoing isillustrative of the present invention and is not to be construed aslimited to the specific embodiments disclosed, and that modifications tothe disclosed embodiments, as well as other embodiments, are intended tobe included within the scope of the appended claims and theirequivalents.

What is claimed is:
 1. A lighting device, comprising: a printed circuitboard; one or more light emitting units formed on the printed circuitboard; a resin layer which is formed on the printed circuit board, inwhich the light emitting units are embedded; and a diffusion plateformed on an upper side of the resin layer.
 2. The lighting device ofclaim 1, further comprising a light reflection unit which is formed onat least any one of one side and another side of the resin layer.
 3. Thelighting device of claim 2, wherein the light reflection unit is formedin a structure in which the light reflection unit is directly adhered tothe resin layer, or a structure in which the light reflection unit isadhered to the resin layer using an adhesive material.
 4. The lightingdevice of claim 2, further comprising a light reflection unit supportingunit which is formed on an outer surface of the light reflection unit.5. The lighting device of claim 1, further comprising an indirectradiation unit which is formed to be spaced apart from the resin layerand reflects light irradiated from the light emitting units.
 6. Thelighting device of claim 5, wherein the indirect radiation unitcomprises the light reflection unit which is formed on at least any oneof one side and another side of the resin layer, and an indirectradiation air gap is formed between a side of the resin layer and thelight reflection unit.
 7. The lighting device of claim 6, furthercomprising a support unit which is formed on the outer surface of thelight reflection unit and in a lower part of the printed circuit board.8. The lighting device of claim 2, wherein the light reflection unit isformed of a material including a white pigment or a metal.
 9. Thelighting device of claim 1, wherein the printed circuit board iscomposed of a flexible printed circuit board.
 10. The lighting device ofclaim 1, wherein the light emitting units are composed of side view typelight emitting diodes.
 11. The lighting device of claim 1, wherein afirst air gap is formed between the resin layer and the diffusion plate.12. The lighting device of claim 1, further comprising a reflectionmember which is formed between the printed circuit board and the resinlayer and has a structure in which the light emitting units pass throughthe reflection member.
 13. The lighting device of claim 12, wherein areflection pattern is formed on the reflection member.
 14. The lightingdevice of claim 13, wherein the reflection pattern is formed with areflective ink including any one of TiO₂, CaCO₃, BaSO₄, Al₂O₃, Siliconand PS.
 15. The lighting device of claim 1, further comprising a firstoptical sheet which is formed on an upper surface of the resin layer anddiffuses emitted light.
 16. The lighting device of claim 15, furthercomprising a second optical sheet formed on the first optical sheet. 17.The lighting device of claim 16, wherein an optical pattern forshielding or reflecting the light emitted to an upper surface of thefirst optical sheet or a lower surface of the second optical sheet isformed.
 18. The lighting device of claim 17, wherein the optical patternis formed in a structure in which a diffusion pattern formed using alight shielding ink including one or more materials selected from TiO₂,CaCO₃, BaSO₄, Al₂O₃ and silicon overlaps with a light shielding patternformed using a light shielding ink including Al or a mixture of Al andTiO₂.
 19. The lighting device of claim 18, wherein the diffusion patternis formed in a structure in which it is printed on at least one surfaceof an upper surface and a lower surface of the light shielding pattern.20. The lighting device of claim 1, wherein the resin layer is composedof an ultraviolet curing resin including a oligomer.
 21. The lightdevice of claim 20, wherein the oligomer comprises any one materialselected from urethane acrylate, epoxy acrylate, polyester acrylate andacrylic acrylate.
 22. The light device of claim 1, wherein the resinlayer further comprises beads composed of any one selected from silicon,silica, glass bubble, PMMA, urethane, Zn, Zr, Al₂O₃ and acryl.
 23. Thelighting device of claim 6, wherein the light reflection unit is formedof a material including a white pigment or a metal.